Fuel cells using a polymer membrane such as sulfonated fluorinated polymer membrane-like materials sold under the trademark NAFION by E.I. dupont de Nemours and Co. are known in the art. Such fuel cells typically operate in a pressure range of from one atmosphere to about five atmospheres, and at relatively low temperatures, i.e., temperatures which are below the boiling point of water. The hydrogen fuel source for such fuel cells is typically natural gas which must be chemically treated, or "reformed" so as to raise the percentage of hydrogen in the fuel gas, and to remove contaminants. One problem with using gaseous fuels for solid polymer electrolyte fuel cells relates to the tendency of the membrane to dry out during operation. In order to operate efficiently, the electrolyte membrane must be kept moist. Moisture for the membrane can be derived from product water formed during operation of the fuel cell. Additional moisture for the membrane can be obtained by humidifying the reactant gases as they are being fed into the anode and cathode reaction chambers. Polymer membrane cells, while operating at relatively low temperatures as compared to other types of fuel cells, will perform most efficiently when operating in the upper end of their operating temperature range. Higher operating temperatures, however, serve to exacerbate the dry-out problem. As noted above, natural gas fuels also require refining or reforming to increase the hydrogen concentration in the fuel gas and to eliminate contaminants.
The desirability of using liquid fuels to provide the reactant for the anode side of the polymer membrane fuel cell has been noted by the prior art. The use of relatively high purity liquid fuels such as methanol, ethanol or other alcohols as a reactant for fuel cells has been recognized as being desirable in U.S. Pat. Nos. 4,390,603, granted Jun. 28, 1983; U.S. Pat. No. 4,828,941, granted May 9, 1989; and U.S. Pat. No. 5,132,193, granted Jul. 21, 1992. One problem with using liquid methanol, or other liquid alcohols, as a fuel source for a solid polymer membrane electrolyte fuel cell relates to the fact that a portion of the liquid methanol fuel will diffuse from the anode chamber through the electrolyte membrane into the cathode chamber. Once the methanol fuel enters the cathode chamber, the conventional platinum cathode catalyst will oxidize the methanol on the cathode side of the membrane thereby resulting in lower cell performance, and heat generation. The use of liquid methanol fuel thus lowers performance of the cathode, and results in a loss of the methanol fuel.
Recent developments in cathode catalysts have resulted in the identification of cathode catalysts which can be used in solid polymer electrolyte fuel cells, and which will not oxidize methanol to any significant degree. Examples of such cathode catalysts include: iron tetramethoxyphenylporphyrin; iron tetramethoxyphenylporphyrin +RuO.sub.2 ; iron octaethylporphyrin; iron octaethylporphyrin +RuO.sub.2 ; cobalt tetrapyridylporphyrin; cobalt tetrapyridylporphyrin +RuO.sub.2 ; iron tetrapyridylporphyrin; iron tetrapyridylporphyrin +RuO.sub.2 ; and iron tetranitrophenylporphyrin. Eastman Kodak Company has the ability to produce the aforesaid catalysts. It would be highly desirable to provide a liquid methanol-consuming fuel cell system which utilizes a solid polymer electrolyte membrane and which would provide for efficient consumption of the methanol fuel.